roger wicker and to president obama. two rounds of preliminary tests suggest the letters contain ricin, a poison than originates in castor beans. however, definitive tests on the letters are still being conducted. white house spokesman jay carney said the president was never in danger. >> materials that are suspicious or substances that are found to be suspicious at remote locations are then sent for secondary and more intense testing, and that process is under way now. >> reporter: the f.b.i., after reviewing the letters, says for now there is no indication of a connection to the attack in boston. the letters were mailed from memphis, tennessee, last week on april 8 and seemed to have come from one individual who wrote this: >> reporter: because the other reason that the f.b.i. sees no connection to boston is a matter of timing. kenneth curtis of tupelo, mississippi, has been taken into custody and charged with sending the letters. the f.b.i. believes curtis has sent over letters with similar content to other members of